Detailed investigations continue on the molecular basis of the calcium and phosphate absorption system, and the effect of vitamin D-dependent calcium-binding protein (its binding properties, amino acid sequence, crystal structure), the molecular and cellular basis of the diffusional and active transport systems for calcium, the molecular basis of phosphate transport, the identification of the 1,25-(OH)2D3-like component in the calcinogenic factor in Cestrum diurnum and characterization of the glycosidic moieties on the latter factor. BIBLIOGRAPHIC REFERENCES: H.J. Armbrecht and R.H. Wasserman. The Enhancement of Calcium Uptake by Lactose in the Rat Small Intestine. Fed. Proc., 1976 (Abst). H.J. Armbrecht and R.H. Wasserman. Enhancement of Ca++ Uptake by Lactose in the Rat Small Intestine. J. Nutr. 106: 1265-1271, 1976.